Periscope and the like.



J. W. HASSELKUS. PBRISGOPB AND THE LIKE.v APPLIGATION FILED 00T. 2a, 1911.

3l GKQ@ l Patented Dec. 10, 1912. f E 2 SHEETS-SHEET 1.

m TTORNELKS J. W. HASSELKUS. PERISGOPE AND THE LIKE.

APPLICATION FILED 0012.28, 1911.

lI i

/ ATTor/vers muren scieries iTENT oniiioii.

JOHN WLLIAM HASSELK'S, 0F CLPHAM COMMON, .LONDONQ ENGLAND; ASSIGNOR T0 ROSS LIMITED, 0F CLAPHAM COMMON, IAONDO}\T, ENGLAND.

rsaiscorn AND 'rim LIKE.

Specification of Letters Patent.

i Patented Demo, 191e.

Application filed October 28, 1911. Serial No. 657,321.

To all whom, t may concern.;v

Be it known that I, J oHN WrLLiAM HassnLKUs, a subject of the King of Great Britain and ireland," of 3 North Side, Clapham Common, in the county of London, England, have invented new and useful Im- '.provements iii Feriscopes and the Like, of

which the following 1s a specification.

This invention relates to periscopes and the likeadapted to be used to obtain, as required, either a view equivalent to that seen by the naked eye, or an enlarged view as seen through a telescope of suitable power, and this invention relates more especially to instruments which are to he used .tor the sighting of objects from protected positions, such as, for instance, fromships turrets, or the like, for looloout purposes, or for sighting accurately for gun-fire.

The principal objectA of this invention -is to provide` an instrument in which `the two optical systems which provide for the afore said views are so combined that they form a completely self-contained instrument, without auxiliary lenses, or prisms, having to be moved into, and out of, the path of the rays for the purpose of obtaining one2 or the other, view as required, Athus avoiding all danger oit disarrangement of the instrument from this cause. Thelight can be shut oli trom either optical system as 'required by means of disks, shutters, or blinds, which can be carried quite distinctly from the in strumeiit itselt, although (as such disks, shutters, or' blinds, can be very light) they can be carried by the instrumentif desired.

The optical portion of the instrument to give the enlarged view mayconsist of a telescope of xed power, or ofthe type known as the variable power telescope, with asighting cross. The telescope is arranged in such manner as to forma periscope by means of upper and lower prisms. The lenses may be such as are usually employed in telescopes of this description.

The augriliary optical portion which provide-s tor the view corresponding. to that seen by the naked eye comprises a combination olenses, which collect therays from the object, and an ordinary right angular erecting prism which deflects the rays at an angle of 90, orthereahout, besides causinga .sidewise reversal of Athe image.. To reverse the image a ain, but in the vertical direction, the bun le of rays which leaves t the erecting prism is caused to pass through the upper of the aforesaidprisms, utilizing a polished -surface thereotI as a totally reflecting surface which causes the second reversal of the rays.l After the rays leave the said upper prism, prism which changes the direction or the rays so as to make them parallel, or nearly so, to the course they followed before enter# ing the said up er prism. To complete the auxiliary opticL portion, an achromatic lens is interposed in the pat-'h ot the rays to make them parallel to each other before they impinge upon the object glass of the main telescope, and then the rays take a course through the complete telescopic system in a similar manner to all the rays enteringthe aforesaid upper prism. The said achromatic lens may be to the rear of the aforesaid prism, which receives the rays from the upper prism, or in any convenient place along the path of the rays, for example it may be placed directly after the lens combination, or after the Amici prism, orbetween the upper prism and the prism be they pass throuoh a prism being utilized for the reversal o the image in the vertical direction, a special prism may bev used for the purpose and instead of the rays passing through the aforesaid small prism to bring them parallel, or nearly so, to the course theytook before entering the said special prism, they may pass through a prism cemented to the hy otenuse of the upper prism, or, it' desired, t e erecting prism may be replaced by an ordinary right angle reflecting prism similar to the upper prism, and the special reversing prism he dispensed with. The necessary reversal of image m'ay them be eiiected by erecting lenses, or prisms, for instance, an arrangement of lenses, such as are used in the main telescope, orother types of erecting telescopes. Tlie rays from this auxiliary arrangement will pass through the prism prism as` aforesaid.

vcemented tothe hypotenuse of the upper The accompanyingdrawings illustrate an -i instrument constructed according` to this invention,.but I do not limit niysel to the preciseecnstruet-ion illustrated.

Vbe also utilized to close the aperture to the Figure 1 is an elevation of the instrument. Fig Q is an lelevation of the upper part of Fig. 1` at right angles thereto, Fig. 3 is a longitudinal section, and Figs. Il and 5 are Sections, respectively along the lines a a and b Fig. 3. i

The optical portion of the instrument to gire the enlarged view consists of a telescope of the type known as the variable power telescope, .2 being the object glass, 3 the collecting lens, 4 the transparent glass plate with a sighting cross etched thereon, 6 the erecting lens and 7 and 8 the lenses of an eye-piece of the Ramsden type. By altering the distances between the, sighting cross 4l: and the erecting lens ti and the eye piece, the power is varied in the usual manner. It is unnecessary to particularly describe this portion ot the instrument as its construction and operation may be ot the usual, or any suitable, kind. By the introduction of the right angled prisms 1 and 5, the telescope is made to constitute a periscope with any predetermined displacement et the sighting line.

If desired, instead of the variable power telescope, an ordinary erecting telescope of a suitable fixed power can be used in conjunction with the prisms constituting the periscope, andin the place of the transparent glass plate f1 with etched sighting lines, other cross lines, such as lines made of wire. or spiders web, for example, may be used land a device, or devices, suc i as are indicated at 15, may be used for illuminating through a passage, or passages, 16 the lines at night. The auxiliary optical portion which provides for the view corresponding to that seen by the naked eye comprises a combination of lenses 9 and 10 by which thel rays are collected from the object, an erectingprism 11 which causes the image to be reversed in vert-ical plane, a prism 12 'for the purpose of deiiectinglthe rays at an angle of 90, or thcreabout, and ot reversingthe image in the horizontal plane, and an achromatic lens 13 which causes the rays to emerge as parallel rays betere they strike the small prism 14 cemented upon the hy potenusc of the prism 1, so as to enable the said rays to pass uninterrupted to the object glass 2' which they traverse and emerge at the eye-piece to form an in'iage, corrcsponding to that seen by the naked eye. To obtain this view it'is desirable to close the aperture 17 leading to the prism 1, which can be done by 1n fans of the shutter 1S which is shown as being hinged at Vt9 so thatI it can lens combination 9 and 10 when it is desired to use the instrument. as a telescope. The said shutter can be operated by any suitable means, such, -tor instance, as a cord passed over the wheel 20. The auxiliary optical system comprising tially as seen by the naked eye, and the other the lenses 9 and'lO, prisms'A 11, 12, and achromatic lens 13, should, of course, possess a negative power equal, or nearly equal, to the power ot' the main telescope.

If desired, the arrangement of the auxiliary optical system may be moditicd, for instance, the reversals of the image in both places may be ettected through an arrangement of lenses, or prisms, for instance, an arrangement of lenses, similar to that employed in the main telescope, in which case the erecting prism will be dispensed With and the Amici prism be replaced by a right angle prism similar to the prism 1 used with the main telescope, or the prism 1 of the main telescope may be utilized as an erecting prism; in this case the Amici prism is retained and a small right angle prism is placed beneath the prism 1 to bring the rays into a course parallel, or nearly parallel, with the axis of the main telescope.

Having now particularly described and ascertained the nature of my said inven tion and in what manner the same is to be performed, I declare that what I claim is 1. An instrument of the type described, cmnprising two optical systems,the elements ot which are arranged in constant predetermined rclation, one of said systems giving a. materially magnified periscopic image and the other giving a periscopic image substantially cmresponding to thatI of the naked eye, said systems having a common sighting field whereby without alteration of the position ot the elements of said optical systems, an object may be viewed in said common field through the one system upon the exclusion ot light from the other system, and vice versa. substantially as described. l,

2. An instrument of the type described,

comprising independent lightreceiving apertures, a common field of view, and two periscopic optial systems, one giving an image, substantially as seen by the naked eye, and the other giving an image materially magnified, the elements of said systems being constantly so related as to bring their respective images into axial coinci` dence in said common field of view, whereby, without alteration of the position of the elements of said systems, an object may be viewed in said common field through the one system upon the exclusion of light from the other systeln and vice versa, substantially as described.

3. An instrument of the type described, comprising independent light receiving apcltures, a. common locating sight, pcriscopic optical systems respectively conununicating with said apertures Aand converging the. images received theretrom upon said locating sight through ditl'erent paths. of light travel, one of said systems giving an image substangiving an image materially magnified, and

l an eye piece common to both optical systems through which the images converging on said common locating sight may be viewed. i

4. An instrument of the type described, comprising amain optical system to give an enlarged image, an auxiliary system to give.

an image substantially as seen by the naked eye, a common locating sight for said systems, and means for converging the light admitted'to said systems upon the common locating sight, -said systems communicating' With independent sighting apertures, substantially as described.

, 5, An instrument of the type described,

l comprisingl a main optical system to give an enlarged image, an auxiliary system to give an image substantially as seen by the naked eye, a common locating sight for said systems, and means for converging the light 'admitted to said systems upon the common 'locating,sight, said systems communicating two subscribing Witnesses.

HASSELKUS.

JOHN WILLIAM Witnesses v CHARLES W. CROCKER,

HERBERT D. JAMESON. 

